We present a 2-υm frequency comb based on a reliable mode-locked Er:fiber laser with 100 MHz repetition rate. After shifting the spectrum of the amplified Er:fiber comb to longer wavelengths, a single-clad Tm/Ho:fiber is used as a self-pumped pre-amplifier to generate a coherent and broadband spectrum centered at 1.93 υm. Subsequently, a cladding-pumped Tm:fiber amplifier boosts the system to a maximum output power of 4.8 W at 1.96 υm. After compression in a compact grating compressor, our Er:fiber/Tm:fiber hybrid system delivers as much as 2.9 W with a pulse duration of 141 fs. The systems comb properties are examined via heterodyne measurement.
Citation: Optics Letters
Pub Type: Journals
fiber amplifiers, fiber lasers, frequency combs, frequency noise, infrared lasers, nonlinear optics, supercontinuum generation, Thulium-doped lasers, ultrashort pulses